Mopiqtt

* Added `mopidy/cmnd/queryschemes` to request a list of uri-schemes Mopidy can handle in searches
* Added `mopidy/stat/uri_schemes` to get a list of uri-schemes Mopidy can handle in searches
* Added `mopidy/cmnd/search` to search libraries for any string (artist, album, track)
* Added Added `mopidy/stat/search_results` to get results of search command

* Fixed bug on `mopidy/cmnd/plrefresh`
* Class name renaming

* Improved error catching
* Added `mopidy/stat/trklist` message showing the list of tracks in the queue
* Added `mopidy/cmnd/chgtrk` to change current playing track in tracklist

* Fixed bug on `mopidy/cmnd/add`
* Added `mopidy/cmnd/pstream` to load and play a radio stream (or any single track)
* Added `mopidy/stat/refreshed` event when playlists have been refreshed
* Added `mopidy/stat/plrefresh` to refresh one or all playlists

* Better playlist list formatting **Breaking change:** Now the list is an array of objects
* Introducing position of current playing track

* Added `mopidy/cmnd/ploadshf` to load and play shuffled playlists